Telephone-receiver.



J. L. SPENCE. TELEPHONE RECEIVER. APPLICATION FILED JUNE 6, 1913.

1,1 12,392. Patented p 29, 1914.

' UNITED sfrnTEs PATENT o en,

' JESSE. L. srinvqn, or NEW YORK, -1v. Y., assreNoR ro EnEcritrcAL EXPERIMENT COMPANY, me, A coaroaarron or NEW YORK.

TELEPHONE-RECEIVER,

To all whom it may concern Be it known that I, Jesse L. SPENGE, a citizen of the United States, residing at New York, in the county of N(W York and State of New York, have invented certain new and useful Improvements in Telephoneothers skilled in the art to which it appertains to make and use the same.

The present invention has reference to an sion and to a specific mechanical means for practising the same. 1

The principal object of the invention is the transmission of sounds in their original purity, free from distortions or modifications introduced by the characteristics of the instrument, and more particularlyto deliver at the receiver a sound of such considerable magnitude combined with clearness ofenunciation as to make it possible clearly to hear spoken words at some distance from the receiver.

One of the principal causes of the transmission or telephones of distorted or modified sounds is found in the fact that the diaphragms used are so mounted as to impose! upon the controlling magnetic waves an ex'-"' ternal or artificialvibratory law, due either to their own bending or to the law of vibration of attached springs.

,"My method of operation involves the use of diaphragms so mounted as to yield as a wholeto the magnetic impulses, producing movements of translation only. Such diaphragmsare substantially inflexible under the stresses to which they are normally exposed. It is one feature of my method that I preserve freedom from external vibratory laws in my diaphragms.

The specific mechanical means preferably employed in putting into. practice my invention is shown in theaccompanying drawings where1n Figure 1 1s a vertlcal section of a receiver,

Fig. 2 is a face view of the same after removal of the cover ordinarily employed.-

1 Within the casing 10 is mounted the usual magnet 11 preferably arranged with its two pole pieces 12 presented symmetrically on opposite ,sides of the center of the diaphragm 13. This arrangement lessens any possible tendency to flexure of the diaphragm under the influence ofa sudden and violentchange of magnetic force.

.Thediaphragm 13. is'givenan aperiodic mounting with its edge against a delicate K j in cushion between it and the magnet, and Receivers; and I do hereby declare the following to be a full, clear, and exact description of the invention, such as will enable this mounting involves a pressure against the cushion so light that said cushion ylelds readily, during use of the receiver, permitting a movement of transla =1 tion of, the diaphragm, substantially without l flexure thereof. This mounting preferably improvement in the art of sound transmistakes the form of a pair of such cushions 14 and 15 of annular shape and having thin rubber Walls. I have found that, within the expect-ed limits of vibration, these cuhsions oppose a substantially constant resistance and do not impose any external vibratory law upon the movements of the diaphragm as would be the case with springs attached to the same. The cushions and diaphragm are kept in place by a cover 16 having the usual opening 17 for thesound.

I have found that a recelveri constru'cted as described produces a movement of substantially pure translation in the diaphragm 841 l which preservesits parallelism to the plane of silence; and that singularly correct voice I transmission is obtained with great sound volume. a v

It will be seen that my improved receiver comprises a'diaphragm, mounting-cushions and magnet so constructed and proportioned, as to magnet strength, diaphragm thicknessand delicacy of air cushion mounting, that the diaphragm has a practically 9b a eriodic action under the expected conditlons of: use. For this urpose it is only necessary that the mutua pressures-exerted between dia hragm and cushion during normal use, sha be consistent with delicate, re-

- sponsive and practically aperiodic resilience in the cushion; while, at the same time, such 7 pressures shall never be sufiicient to produce such a flexure of the diaphragm as will materia-lly affect the quality of sound production.

' I am aware that air cushions have been used in .certain classes of acoustic instruments for the purpose of firmly clamping the edges of the diaphragms intended to act by flexure. Diaphragms so mounted and operatingare not aperiodic in nature, but tend to impose a vibratory law fore gn to Patented SeptQ29, 1914. x.

- vers attached to that of the sound to be projected; especially when associated with external springs or lethe diaphragm.

I have found that, where a relatively rigid diaphragm is lightly enough confined against a pneumatic cushion at its edge, this cushion exerts an ap er1od1c resilience, which leaves against the edge of said the diaphragm free to conform its movements as a Whole to the particular vibrations whlch correspond to the magnetic changes in the telephone receiver. Such a cushion act merely to hold up the diaphragm when current is cut off, and to preserve its proper v angular position with respect to the magnet at all times. It also affords a of air around the edge of the diaphragm and increases the eificiency of pro ection of sound Waves from its surface;

I do not limit myself tothe details of construction described, as be made withou tion. I

What I claim is 4 1. In a telephone receiver, a. magnet and a diaphragm sufficiently stifi to be substantially inflexible under the operating stresses for which it is, designed; in combination with a yielding aperiodic mounting therefor,

bar to passage departing from the inven- 6 substantially as described.

2. In a telephone receiver, a magnet and a diaphragm sufficiently stifi' to be substantially inflexible under the operating stresses for which it is designed; in combination with a delicate pneumatic cushion placed diaphragm on the side toward said magnet, and exerting a pressure at all times light enough to permit ing against the same various changes may I said cushion to yield readily to the movements of the diaphragm incident to operation, substantially as described.

3. In a telephone receiver, a magnet and a diaphragm sufiiciently stiff to be substantially inflexible under the operating stresses for which it is designed; in combination with a pair of delicate air cushions confining the edge of said diaphragm and pressso lightly as to permit said cushions to yield readily to the movements of the diaphragm incident to operation, substantially as described.

' 4. In a "telephone receiver, a magnet, a delicate air cushion, and a substantially inflexible diaphragm confined in light contact at its edge with said cushion and free of all attachment save at its edge, substantially as described.

5. In a telephone receiver, a magnet, a pair of delicate air cushions, and a substantially inflexible diaphragm confined by light pressure between said cushions at its edge and otherwise unattached, substantially as described.

'6. In a telephone receiver, a substantially inflexible diaphragm, a yielding aperiodic mounting therefor, and a magnet having two poles presented on Opposite sides of the center of said diaphragm, substantially as described.

In testimony whereof- I afiix in presence of two witnesses.

JESSE L. SPENCE. Witnesses: v I

, KATHARINE C. MEAD,

H. S. MAC KAYE.

mysignature, 

